Medical products manufacturers and clinicians, including blood collection and storage operators, have frequent need to make a fluid transfer between two or more sterile containers or systems by way of tubing connecting these containers. In the manufacturing environment, it is often necessary to sterilize components or subassemblies of a drug or device by different methods. For example, in a complex product incorporating both a fluid container and a dry set assembly, the solution container may be steam sterilized whereas the set or other components would not be compatible with steam processing. In such a case, the dry components may be terminally sterilized with gas or radiation. The problem arising herewith is how to join these components together as an integrated sterile product when the sterility of the components is compromised in the process of making the connection. In the typical clinical setting, contents from a blood collection container need to be transferred to other sterile containers. Again, the process of making the connection may compromise the sterility of both systems to be connected.
Technologies are currently available and in use in the marketplace to address this need. These technologies may be grouped into three different approaches to the problem of sterility. The first group seeks to maintain the sterility of the connected area through passive means including contamination control measures. A second endeavors to create a sterilizing field or plasma in which the connection is effected. A third approach performs a terminal sterilization on the affected area after the connection is completed. The present invention utilizes this terminal sterilization approach which is considered very reliable with respect to sterility assurance.
Prominent among current technologies is a patented process that incorporates a high voltage ( greater than 300 Kev) electron beam to sterilize the connection. In this process (U.S. Pat. No. 5,009,654 and 5,496,302) tubing leading from components sterilized individually by separate methods is clamped near their terminal ends to maintain sterile integrity during the connection process. Each terminal end is cut off, removed, and the ends are then connected together by heat-sealing, solvent bonding, or other methods. Radiation is then applied to the area between the clamps to terminally sterilize and then clamps are removed, opening a sterile pathway. The present invention incorporates some aspects of the above process with additional steps and elements, which serve to create a significant improvement.
The prior technology to which the present invention is most relevant is deficient in its economy. The cost to implement and operate a high voltage electron beam system is high. Special facilities expense is necessary to provide shielding from x-rays and to assure that the possibility for human exposure is minimized. Customized materials handling equipment is required to transport product through the electron beam system. The factory floor space required exceeds that of the present invention.
The present invention addresses these deficiencies in that certain alternate energy sources such as pulsed UV light sterilizing systems operate at faster rates, within a smaller floor space, and at less cost than high voltage electron beams. The system also operates without creating ionizing radiation or other potential work environment hazards. In order to gain these benefits, a new assembly process comprising the steps described in this application is necessary.
This invention relates generally to the field of medical drug and device manufacturing, to the field of clinical medical device operations, and more particularly to a process for effecting sterile connections of medical tubing by way of terminally sterilizing an isolated fluid filled connected area.
The primary object of the invention is to provide a sterile connection by terminally treating an isolated connected area after it is resealed.
Another object of the invention is to enable light energy to be employed for terminally sterilizing tubing connections.
Another object of the invention is to provide a more cost effective alternative to methods employing ionizing radiation.
A further object of the invention is to permit implementation of sterile connection technology with less facilities and installation investment than ionizing radiation alternatives.
Yet another object of the invention is to reduce factory floor space requirements from that required by ionizing radiation alternatives.
Still yet another object of the invention is to enable higher levels of microbial inactivation than that provided by other non-ionizing radiation alternative methods such as continuous wave ultraviolet radiation.
Another object of the invention is to take opportune advantage of fluids present in the tubing to be connected.
Another object of the invention is to permit use of a range of olefin polymers for the tubing material.
Other objects and advantages of the present invention will become apparent from the following descriptions, taken in connection with the accompanying drawings, wherein, by way of illustration and example, an embodiment of the present invention is disclosed.
In accordance with a preferred embodiment of the invention, there is shown a process for effecting sterile connections of medical tubing by way of terminally sterilizing an isolated fluid filled connected area having the steps of isolating the terminal ends of two tubing leads to completely close the respective leads to the passage of contaminants; removing the sealed terminal ends of each tube; joining the resulting open ends of the respective tube leads together so as to provide a hermetic seal and creating a non-sterile zone; further isolating a portion of fluid present in one or both of the tube leads adjacent to said zone; introducing said isolated fluid into said non-sterile zone; exposing the non-sterile zone to means for sterilizing all fluid and surfaces inside said zone; and removing any remaining isolation means to open a sterile fluid pathway.
In accordance with another preferred embodiment, there is shown an apparatus for effecting sterile connections for the flow of biological fluids having two sections of tubing having a high ultraviolet light transmission coefficient, wherein said tubing is joinable and selectively isolatable in sections for exposure of selected sections to sterilization means to create a sterile fluid path in joined tubing.